1. Field of the Invention
This invention is in the field of cutting or reaming by use of a rotating axially moving tool wherein a precalibrated guide fixture is provided for ready use by a machinist for reaming the piston pin end bushings of connecting rods having various different lengths as well as different crankshaft and piston pin journal diameters.
In the light of the great variety of imported automobices in the United States, such as Volkswagen, Toyata, Capri, Opel, etc., which require expert engine maintainence, there is now a great need for precision engine rebuilding especially in view of the emphasis on energy conservation. Repair and rebuilding are obviously more most efficient and energy efficient for the small economy cars than scrapping and disposing for new replacement. Accordingly, there is a great need for more accurate and easily used labor efficient tools and work holders to serve in engine rebuilding, particularly the imported engines.
2. Description of the Prior Art
The following United States patents are deemed to be of interest with respect to the present invention.
__________________________________________________________________________ Patent No. Issue Date Title __________________________________________________________________________ 1,331,052 February 17, 1920 Machine for Truing Connecting Rod Bearings 1,369,472 February 22, 1921 Parallel Alignment Fixture 1,520,623 December 23, 1924 Device for Boring Connecting Rods, etc. 1,592,617 July 13, 1926 Boring Mechanism 1,622,560 March 29, 1927 Aligning Machine for Connecting Rods, etc. 2,137,484 November 22, 1938 Connecting Rod Aligner 2,349,526 May 23, 1944 Boring Machine __________________________________________________________________________
From a review of the above-listed patents, one can determine that the art of precision reaming bushings in connecting rods is quite well developed. However, all of the above-mentioned patents are concerned with reaming out the crankshaft or driveshaft ends of connecting rods and not the piston pin ends.
Pat. No. 2,137,484, for example, discloses a fixture for holding connecting rods of different lengths with a sliding plate 34.
Pat. No. 1,331,052 discloses a similar arrangement employing a longitudinal slide 7.
Pat. No. 1,369,472 discloses a pivoted lever type of arrangement for accommodating different connecting rod lengths.
Pat. No. 1,520,623 discloses a fixture employing an elongated slot 9 for accommodating different connecting rod lengths.
In contrast to the prior art devices, the present invention provides a fixture which may be mounted in a common bench vise and which employs a rotatable eccentric member that adapts the fixture in an ingeneous manner by a simple rotational movement of the eccentric member to allow for the precision reaming of the bushing in the piston end of various different size connecting rods. The fixture further provides an indexing means and stop means which cooperate with the eccentric member to allow easy and readily repeated rotational movement of the eccentric member to a desired and precise index position for accommodating different length connecting rods. As will be apparent from the following detailed description and drawings, the fixture is extremely versatile and may readily be adapted to accommodate not only different connecting rod lengths but also various reamer shank diameters and various sizes of crankshaft journals as well and may be easily and repeatedly adapted to work of any new dimensions within reasonable constraints.